In this paper, we utilize the well-known Book-Crossinghttp://www2.informatik.uni-freiburg.de/~cziegler/BX/ dataset that contains \(1,149,780\)  anonymous explicit and implicit ratings of approximately \(340,556\)  books made by \(105,283\)  users in a 4-week crawl (August - September 2004) [1]}. From the dataset, we first removed all the implicit ratings, then we removed users who had fewer than 5 ratings so that the retained users were those who were likely to have rated enough long-tail items.The limit of 5 ratings was also used to remove distant long-tail items. Once short-profile users and distant long-tail items are removed, the Book-Crossing dataset consists of \(6,358\)  users who rated \(6,921\)  books, totaling \(88,552\)  in ratings. In the following, we will address the first research question. Table REF  shows the characteristics of the Book-Crossing datasets.
